The mass migration, known in Chinese as chunyun, is on track to reach an unprecedented scale in 2014. According to Lian Weiliang, the deputy head of China's National Development and Reform Commission, an estimated 3.62 billion trips will be made during the 40-day period surrounding the holiday, an increase of roughly 5.8 percent, or 200 million trips, compared with 2013.

For migrant workers, many of whom face demanding jobs far from their hometowns, the Spring Festival presents a once-a-year opportunity to return home and reunite with their families.

"It's not always easy to afford train tickets, and the journey can be tedious and unpleasant," said Zhang Xuan, a 25-year-old graphic designer who is traveling from Beijing to her hometown in central China's Henan Province. "But not returning home is not an option-my parents would kill me."

According to Liang Xiao'an, a spokesperson for the Ministry of Transport, about 3.2 billion trips are expected to be made by road, including long-distance buses and an increasing number of private cars. Roughly 258 million train trips will be made during the period, while another 42 million people are expected to fly home.

The Baidu map allows users to view the country's most traveled routes (in Chinese only), with a feature that ranks cities based on the number of departures and arrivals that they record. To no one's surprise, Beijing and Shanghai, two of China's most populous cities, were consistently at the top of these charts on Thursday, the eve of the Lunar New Year.

Based on the map, most of the routes are concentrated in China's eastern region, particularly in the southeast, where rapid economic development has lured migrant workers from all corners of China. By contrast, the country's western region, which includes Tibet, Inner Mongolia, and the predominantly Uighur province of Xinjiang, remains mostly untraveled.

Some locals believe that the reduction in car traffic is responsible for an improvement in Beijing's air quality. On Thursday morning, Beijing's skies, which are often smog-filled and hazy, were a brilliant, clear blue.